Our argument uses the topology space of Hintikka chains,
which was used in [1]} and which we now recall.
We remark that this space is homeomorphic to the Stone space of \(\mathrm {FO}_1^{\mathrm {local}}\)  studied in [2]}, [3]}, [4]}.
Hintikka sentences are maximally expressive sentences with a certain quantifier depth, and,
informally speaking, Hintikka chains form a local variant of this notion with a single free variable.
